Wind turbines are erected preferably at locations having high wind speeds which are as constant as possible. Low temperatures frequently prevail at such locations, and so ice can form on the rotor blades under particular weather conditions. The development of ice on the rotor blades impairs the operation of the wind turbine. Therefore, ice warning systems or deicing systems are used in cold regions.
An ice warning system ensures that the wind turbine is shut down as a preventive measure under the relevant weather conditions. This results in losses in terms of yield. A deicing system prevents ice crystals from forming on the rotor blades. Thus, a deicing system makes it possible to leave the wind turbine in operation and to reduce or even avoid losses in terms of yield.
It is known from the state of the art to install heating elements on the external surface of the rotor blades of a wind turbine. Heating elements are preferably installed in regions close to the center of the blade up to the blade tip, where the formation of ice crystals impairs the aerodynamic effectiveness of the wind turbine rotor blades and is thus disruptive. Such heating elements are connected to an electrical energy source of the wind turbine via electrical lines which lead to the rotor blade root from a blade tip end and from a blade root end of the heating element, which electrical lines are made of conventional cables.
The publication WO 2011/127997 A1 discloses arranging a heating mat, which runs in the form of a loop, on the outer side of a wind turbine rotor blade. The electrical connections of the heating mat are located at the two free ends of the loop-shaped heating mat close to the blade root. From there, a first section and a second section of the heating mat each lead to the blade tip. At the blade tip, the heating mat is redirected, so that the two sections merge into each other in a transition region. In one exemplary embodiment, the two sections of the heating mat overlap each other along a leading edge of the rotor blade. In another exemplary embodiment, the heating mat has a third section which can have a further electrical connection close to the blade root. In the known solution, it is not necessary to lead electrical connecting lines to a blade tip end of the heating mat. This is intended to reduce the risk of a lightning strike.